Oracle RAC Scan Listener - (2)

To get scan name details:

These commands will have to executed by grid user.

bash-4.3$ srvctl config scan SCAN name: SMDCMBDBL, Network: 1/XX.XX.10.0/255.255.255.0/nxge7 SCAN VIP name: scan1, IP: /xx.xx.xx.106/10.54.10.106 SCAN VIP name: scan2, IP: /xx.xx.xx.108/10.54.10.108 SCAN VIP name: scan3, IP: /xx.xx.xx.107/10.54.10.107

bash-4.3$ srvctl config scan_listener SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1521 SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1521 SCAN Listener LISTENER_SCAN3 exists. Port: TCP:1521

To get the status of the scan listener:

bash-4.3$ srvctl status  scan_listener SCAN Listener LISTENER_SCAN1 is enabled SCAN listener LISTENER_SCAN1 is running on node kdbpprp2 SCAN Listener LISTENER_SCAN2 is enabled SCAN listener LISTENER_SCAN2 is running on node kdbpprp1 SCAN Listener LISTENER_SCAN3 is enabled SCAN listener LISTENER_SCAN3 is running on node kdbpprp1

The above command shows the hostname on which the 3 different scan listeners are running.

DNS performs the initial load balancing while scan name is called. As 3 IPs are assigned with the
scan name initially though that can be extended later. While clients send request to DNS, DNS
provided three different IP on different request. I.e while we are trying to fetch the DNS with
scan name, we get IP addresses order in different order.

paul@DBBL-ITDD-PAUL:~$ nslookup kdbpprp Server: 127.0.1.1 Address: 127.0.1.1#53 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.162 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.161 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.163 paul@DBBL-ITDD-PAUL:~$ nslookup kdbpprp Server: 127.0.1.1 Address: 127.0.1.1#53 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.161 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.163 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.162 paul@DBBL-ITDD-PAUL:~$ nslookup kdbpprp Server: 127.0.1.1 Address: 127.0.1.1#53 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.163 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.162 Name: kdbpprp.dutchbanglabank.com Address: XX.XX.XXX.161 paul@DBBL-ITDD-PAUL:~$

Command to get status for the specific listener scan.

bash-4.3$ lsnrctl  status LISTENER_SCAN2 LSNRCTL for HPUX: Version 11.2.0.4.0 - Production on 29-MAR-2018 14:50:55 Copyright (c) 1991, 2013, Oracle.  All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_SCAN2))) STATUS of the LISTENER ------------------------ Alias                     LISTENER_SCAN2 Version                   TNSLSNR for HPUX: Version 11.2.0.4.0 - Production Start Date                24-OCT-2017 17:57:55 Uptime                    155 days 20 hr. 52 min. 59 sec Trace Level               off Security                  ON: Local OS Authentication SNMP                      OFF Listener Parameter File   /orafs/app/11.2.0/grid/network/admin/listener.ora Listener Log File         /orafs/app/11.2.0/grid/log/diag/tnslsnr/kdbpprp1/listener_scan2/alert/log.xml Listening Endpoints Summary...  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER_SCAN2)))  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=XX.XX.XXX.163)(PORT=1521))) Services Summary... Service "agentdb" has 2 instance(s).  Instance "agentdb11", status READY, has 1 handler(s) for this service...  Instance "agentdb12", status READY, has 1 handler(s) for this service... Service "agentdb1XDB" has 2 instance(s).  Instance "agentdb11", status READY, has 1 handler(s) for this service...  Instance "agentdb12", status READY, has 1 handler(s) for this service... The command completed successfully

Node VIP: Each Database node in Real Application cluster environment has one node IP and one Node VIP
address, The main difference between these two is Node VIP can move to any other system in case
if current owning system is down but Node IP can't do that. When ever a new connection request is made
the SCAN listener listening on a SCAN IP address and the SCAN port is contracted on a client's behalf.
Because all services on the cluster are registered with the SCAN listener, the SCAN listener replies with the
address of the local listener as Node VIP address on the least-loaded node (Each scan listener keeps updated
cluster load statistics) and connection is routed to that node.

Local Listener on the Database server is registered with Node VIP and Node IP address.

bash-4.3$ lsnrctl status listener LSNRCTL for HPUX: Version 11.2.0.4.0 - Production on 29-MAR-2018 14:59:48 Copyright (c) 1991, 2013, Oracle.  All rights reserved. Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER))) STATUS of the LISTENER ------------------------ Alias                     LISTENER Version                   TNSLSNR for HPUX: Version 11.2.0.4.0 - Production Start Date                24-OCT-2017 18:06:15 Uptime                    155 days 20 hr. 53 min. 33 sec Trace Level               off Security                  ON: Local OS Authentication SNMP                      OFF Listener Parameter File   /orafs/app/11.2.0/grid/network/admin/listener.ora Listener Log File         /orafs/app/grid/diag/tnslsnr/kdbpprp1/listener/alert/log.xml Listening Endpoints Summary...  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER)))  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=XX.XX.XXX.61)(PORT=1521)))  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=XX.XX.XXX.60)(PORT=1521))) Services Summary... Service "+ASM" has 1 instance(s).  Instance "+ASM1", status READY, has 1 handler(s) for this service... Service "agentdb" has 1 instance(s).  Instance "agentdb11", status READY, has 1 handler(s) for this service... Service "agentdb1XDB" has 1 instance(s).  Instance "agentdb11", status READY, has 1 handler(s) for this service... The command completed successfully

Local_Listener: This is a database parameter which is used to provide detail of local listener running on
database node itself. In Real Application Cluster environment this has Node VIP address as value.

When a new connection request is made my SCAN Listener, This address is returned to the SCAN Listener and
then connection is made to database local listener. The difference between SCAN Listener and Local Listener
is SCAN listener runs corosponding to SCAN VIP's while Local Listener runs with Node VIP or Node IP address.
SCAN Listener can move to another database node in case of node failure but local Listener doesn't have this
kind of behavior.

SQL> show parameter local_listener NAME                                 TYPE VALUE ------------------------------------ ----------- ------------------------------ local_listener                       string (ADDRESS=(PROTOCOL=TCP)(HOST=XX.XX.XXX.60)(PORT=1521))

Remote_Listener: Each database instance has this parameter set to SCAN NAME of the cluster environment.
SCAN NAME in turn has one or more IP address further called SCAN VIP and each SCAN VIP has SCAN Listener
running on it, so finally each database instance register itself with all SCAN Listeners running across the
clusterware.

SQL> show parameter remote_listener NAME                                 TYPE VALUE ------------------------------------ ----------- ------------------------------ remote_listener                      string kdbpprp:1521

The solo purpose of remote_listener parameter is to register each database instance with all SCAN Listeners
in RAC. This provide information on what services are being provided by the instance,the current load, and a
recommendation on how many incoming connections should be directed to the instance.

Stopping scan listener:

srvctl stop scan_listener [-scannumber ordinal_number] [-force] Example: srvctl stop scan_listener -scannumber 1

Relocate scan listener:

bash-4.3$ srvctl status scan SCAN VIP scan1 is enabled SCAN VIP scan1 is running on node kdbpbrp2 SCAN VIP scan2 is enabled SCAN VIP scan2 is running on node kdbpbrp1 SCAN VIP scan3 is enabled SCAN VIP scan3 is running on node kdbpbrp1 srvctl relocate scan -i -n   Example: srvctl relocate scan -i 3 -n kdbpbrp2 bash-4.3$ srvctl status scan SCAN VIP scan1 is enabled SCAN VIP scan1 is running on node kdbpbrp2 SCAN VIP scan2 is enabled SCAN VIP scan2 is running on node kdbpbrp1 SCAN VIP scan3 is enabled SCAN VIP scan3 is running on node kdbpbrp2